1. Technical Field
The present invention relates generally to stabilization of one or more thrombocytes at ambient temperatures. In particular, the invention relates to formulations, compositions, articles of manufacture, kits and methods for substantially stable storage of one or more metabolically-active thrombocytes at ambient temperatures.
Background
Whole blood is a complex mixture of cells, nucleic acids, proteins and various other analytes. In particular, blood components include, but are not limited to: cells, such as leukocytes (monocytes, lymphocytes and granulocytes), erythrocytes, thrombocytes and circulating tumor cells; nucleic acid molecules, such a circulating-free DNA (cfDNA); polypeptides, such as lipoproteins, albumin and serum proteins, and other various analytes.
Thrombocytes or platelets are anucleated cells that play a key role in the clotting of blood. Thrombocytes are small, disc-like cells that circulate in mammalian blood and are involved in hemostasis. Thrombocytes secrete a wide variety of growth factors that assist in promoting blood clotting and tissue regeneration.
The level of circulating thrombocytes in a healthy individual is controlled within a physiological range of about (150-400)×103 per mm3. Suboptimal levels of thrombocytes (thrombocytopenia) can lead to excessive bleeding, whereas levels exceeding optimal concentrations can lead to the formation of thromboli (blood clots) that can obstruct blood vessels and can lead to higher risk of stroke, pulmonary embolus or myocardial infarction.
Circulating thrombocytes are typically present in an inactivated state, and are maintained in the inactivated state by factors produced by endothelial cells lining the blood vessel lumen. Upon disruption or injury to this endothelial layer, thrombocytes come in contact with collagen or von Wildebrand's factor, which activates the thrombocytes causing the thrombocytes to aggregate (i.e., clot). This activation and aggregation also may occur by the enzymatic activity of thrombin or in the presence of ADP. Upon activation, thrombocytes release the contents of alpha and dense granules that include growth factors and fibrinogen that assist in clot formation and help promote recruitment of fibroblasts to promote wound healing. Activated thrombocytes can be distinguished from inactivated thrombocytes by their more spherical/stellate shape.
The activation, aggregation and/or release of numerous growth factors and other intracellular components of thrombocytes during the collection of whole blood can greatly hinder the quantitation and analysis of these cells. The addition of various anti-coagulants to maintain an inactivated thrombocytes at ambient temperatures results in only about 13-52% inactivated thrombocytes at 24 hours making accurate quantitative analysis of total thrombocytes essentially impossible at this time point. Thus, there exists a need for improved formulations for and methods of stabilizing thrombocytes at ambient temperatures for a time sufficient for storage and shipping thrombocytes for research, diagnostic and therapeutic purposes.